<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="app">
    <button @click="fn(1,2)">click</button>
</div>
</body>
<script src="https://cdn.bootcss.com/vue/2.2.2/vue.min.js"></script>
<script>
    var vm = new Vue({
        el:'#app',
        data:{
        },
        methods:{
            fn:function (a,b) {
                console.log(a,b,event.target)
            },
        }
    })
</script>
</html>